This invention relates to a composition for endodontically treating a root canal, and more particularly to a composition which may be used for filling the inside of the canal after conventional endodontic treatment.
In endodontic therapy (root canal), a dentist often operates on a diseased pulp by filling in the root canal. More particularly, the dentist first accesses the root canal. The dentist then debrides the canal by removing all of the soft tissue (the pulp) contained therein. Once this is completed, the dentist typically irrigates the canal to remove pulpal remnants. Finally, the dentist then enlarges the canal to remove irregularities or rough surfaces therealong so that the dentist can insert into the canal a filling material referred to in dentistry as a "cone" or "point".
Most filling materials comprise a substance known as gutta percha which is a thermoplastic material. Gutta percha is very opaque because it includes a substantial amount of zinc oxide (approximately 70%). Gutta percha is usually applied in the shape of a cone or point of about 1.5 inches long and varying in diameter from 0.010 inches to 0.090 inches.
When using a cone made of gutta percha in a root canal treatment, it is desirable to have the point of the cone terminate at the apex in the canal. In prior methodologies, repeated x-rays of the patient's mouth were required in order to 1) place the point accurately at the apex and 2) prevent the material from going over the apex during seating and compacting. Moreover, this x-ray technique was not always accurate because the apex of the tooth is curved--when it appears on the x-ray that the gutta percha is shy of the apex, it may actually very well be at or over the apex. If the gutta percha is then forced beyond the apex, a pulpal irrigation may be created.
Because of the disadvantage of using x-rays, it has been previously disclosed to use a gutta percha cone that is impregnated with electrical conductive carbon fibers. The cone is inserted into the root canal. Then, because of the presence of the electrically conductive carbon fibers, the dentist is able to measure the proximity of the gutta percha cone to the apex of the canal. As a result, a more accurate determination of where the tooth apex is located is theoretically achieved using this system.
However, the above method of using gutta percha which is impregnated with conductive carbon fibers is less than desirable. Gutta percha is a thermoplastic material which must be heated to force the material to the apex. As the material cools a gap formation occurs at the apex and along the walls of the root. This occurs despite a cement interface between the gutta percha and the walls of the root.
In addition, the use of carbon fibers may be disadvantageous. The carbon fibers may to some extent leak out over time because they have been incorporated into a thermoplastic material. A thermoplastic material such as gutta percha is very weak and inadequately holds the conductive carbon fibers in place therein.
Furthermore, as described, because a thermoplastic material such as gutta percha is used, it is necessary to heat the gutta percha during insertion. When the gutta percha is heated, the conductive materials will tend to migrate away from the center of the gutta percha, further weakening the gutta percha's hold on the carbon fibers.
Accordingly, it would be desirable to have a composition which overcomes many of the disadvantages of using a thermoplastic polymer such as gutta percha and which can incorporate electrically conductive material so that the proximity of the inserted cone to the tooth apex in the canal may be accurately measured.